Well, i purchased a 96 z28 convertible a couple months ago. It only has 96000 miles but i've been having problems .

I keep getting a code 300, multiple random misfire. I've already changed plugs, wires, distributior cap( I'm on my third one, i bought an aftermarket cap, and it ran great for a few days, then it left me walking. I put another one on it and this time i went with AC delco,) so basically, i got new ac plugs,wires,and cap. My fuel pressure checks out ok, and i've already done compression checks on my cylinders and all is ok.
I hooked up a noid light and my injectors check out alright.

Any thoughts or suggestions?

 

ICM? coil? did you change the coil wire when you changed the wires? i had an O2 shorting out (bad extention) and it was throwing the same code. btw update your sig and put any mods.

 

Yes, D00GieStyle, you will get more responses when the board know what you have.

 

i got a 96 z28, six speed ( LT1 of course), all parts are factory except the parts i've been putting on it. It has 96000 miles.
I've installed:
new AC DELCO plugs, 7mm AC Delco wires, AC Delco distributor cap and rotor button.

 

Your injectors can be getting the proper voltage as observed by the noid lights, but they still may not operate properly if they are partially clogged and that can lead to misfiring as well. Also, a faulty EGR valve or vacuum leaks can lead to that problem.

 

I had to put a new EGR valve on it a week after i got it. It was giving a code 400, i replaced it no problem since. I may have a vacuum leak but it runs very bad, so i doubt that. But injectors not pumping at the right psi may be the culprit. I'm leaning towards a problem eith my opti though. it keeps jumping fire inside the cap and i've got a brand new ac delco. I just don't know what would cause irratic fire without throwing a code. I've already installed new as plugs and wires too.

 

Normally if a vacuum leak was the culprit it would cause a lean code P0171 or P0174 (depending on where the leak is) with the P0300.

It's generally recommended to replace the entire optispark distributor as a whole unit instead of replacing just the cap and rotor. Don't go with a parts store one, get yourself an AC delco one from one of the sponsors.